Not applicable.
Not applicable.
The present invention is directed to air cooling systems for electronic equipment and more specifically to a plenum based system for delivering cooing air to an electronic equipment cabinet.
Over the past several decades the advantages of using computers to perform many different tasks has become clear in almost every industry. Even industries once reluctant to embrace new computing tools have been forced to adopt new business strategies that center on computing abilities. Because of this realization many companies and other entities require massive computing and data storage capabilities to support their employees, efficiently manufacture and sell products and provide services to their customers. In fact, not only do computers help businesses to be efficient, but now, most companies could not function without their computing and database capabilities. In effect, computing and database capabilities have become critical to the operations of many companies and other entities such that any disturbance in those capabilities could result in massive loss of business.
To provide the massive amount of computing and database capabilities needed, many companies locate racks of computer servers and other electronic modules in special xe2x80x9ccritical environmentxe2x80x9d computing and warehousing rooms where information technology personnel can monitor and maintain the server configurations. Hereinafter servers and electronic modules of all types will collectively be referred to as electronic modules in order to simplify this explanation. Each rack typically includes a plurality of vertically arranged (i.e., one support above another) shelving members. Each member is configured to support one or more electronic modules. The shelving members are often vertically adjustable so that the space between members can be modified to accommodate differently sized electronic modules.
Because technology is advancing quickly, maintaining servers and databases has become extremely expensive. The expense of maintaining and expanding to meet demanding computing capabilities is exacerbated as IT personnel required to maintain and upgrade such capabilities are typically highly skilled. For this reason an entire server/database xe2x80x9chostingxe2x80x9d industry (e.g., web hosting) has evolved where industry members maintain massive numbers of servers and other electronic modules and effectively rent out the right to use the modules to customers (i.e., businesses). A similar industry, referred to as xe2x80x9cco-location,xe2x80x9d has also evolved where companies provide conditioned space for their customer""s servers, data bases and the like. In both of these industries highly skilled IT personnel can use their expertise to provide services to a huge number of customers thereby spreading costs. In addition, as a customer""s computing needs change, the host can accommodate the needs quickly by adding required modules and subletting additional space in the critical environment.
A cabinet is typically constructed about each rack including top and bottom walls, opposing lateral walls and front and back walls. The front and back walls are often hinged and openable to facilitate access to the modules inside the cabinet. In addition, the front wall is often transparent so that IT personnel can observe the devices inside the cabinet and determine status from various visual displays that may be provided.
Often the electronic modules placed within a rack will be replaced by other electronic modules to modify capabilities or change other important system operating parameters. For example; with the fast pace of hardware innovation servers are often obsolete after just a couple of years and therefore server swapping is common.
One problem with virtually all electronic modules, including computers and computer servers, is that, during operation, electronic modules generate heat. If module generated heat is not dissipated quickly enough, the heat can cause the module to malfunction or, when extreme, can destroy the modules.
The industry has developed several different ways in which to cool electronic modules. For example, in the case of stand alone servers, most servers include one or more fans positioned in a back wall of a server housing. The fans run whenever the server is operating to draw air from the space in front of the server over the heat generating devices inside a module housing.
In the case of critical environments, module fans alone cannot be relied upon to maintain low temperatures. Specifically, fans alone cannot be relied upon because, in a typical critical environment, there are so many heat generating modules pumping heat into the ambient that the ambient temperature in the critical environment would reach dangerous levels relatively quickly. In effect, the ambient air would not be cool enough to effectively cool the modules. Thus, in the case of critical environments, many cooling schemes call for monitoring and cooling the entire critical environment.
One common way to cool critical environments has been to raise the floor in the environment so that a space exists below the surface that supports the module cabinets. Then cooling air is pumped through floor tiles into the critical environment. Environment temperature is then monitored at various locations and the cooling air temperature and/or volume is adjusted to maintain the environment at the desired temperature. Ideally the environment temperature throughout the critical environment should be maintained at the same temperature so that if modules are swapped into or out of a cabinet the modules will always be exposed to the same optimal ambient temperature.
While identical and constant temperatures throughout the critical environment are ideal, unfortunately there are several sources of temperature irregularly in typical critical environments. For instance, in addition to providing cooling air through the raised floor, many critical environments route power and information busses there to conceal the busses and maintain unobstructed paths within the environment. One problem with placing the busses and other cables below the raised floor is that the cables and buses can block air flow to parts of the critical environment above the raised floor thus causing the ambient temperature in some parts of the critical environment to be different than in others. Cabinets (and electronic modules therein) in the warmer room areas tend to be warmer than cabinets in the cooler areas.
One other source of temperature irregularity within the critical environment is the disparate amount of heat generated by the different modules and their uses within the separate cabinets. For instance, assuming identical servers, a first cabinet including three servers that operate near full computing capacity generates more heat than a second cabinet including one server that operates at a small fraction of the server""s capacity. In this case, all other things being equal, the air temperature near the first cabinet (and inside the first cabinet for that matter) would be warmer than the air temperature near the second cabinet.
Thus, despite efforts to maintain the same conditions throughout a critical environment, often the temperatures within different areas of the critical environment will vary and this variance can result in module failure or pre-mature degradation in performance.
One solution to the critical environment temperature disparity problem is to increase the temperature of the cooling air forced into the critical environment so that even the warmest area within the room is cool enough to minimize or avoid module failure. Unfortunately, IT personnel are routinely inside the critical environment during system operations to monitor and work on modules and therefore this solution is often unworkable.
Another solution to the critical environment temperature disparity problem has been to identify temperatures throughout a critical environment at relatively small spatial intervals and then adjust air flow through baffled raised floor tiles within the environment to even out environment temperature. A manual procedure to accomplish this task has required an environment administrator using an air temperature sensor to place the sensor at many equispaced locations within a critical environment and at a specific height (e.g., 2 feet) above the floor surface and take a plurality of temperature readings. The readings are then fed into a computer that generates a three dimensional map of temperature in the environment as a function of location within the environment. Where xe2x80x9chot spotsxe2x80x9d occur the administrator then adjusts tile baffles. Thereafter the administrator again collects temperature readings throughout the environment and causes the computer to generate the map to see the results. In the alternative, instead of adjusting baffle settings, the administrator may actually have cables/buses under the raised floor rerouted where air paths are essentially blocked so that static pressure under the raised floor is more even. Clearly, this solution is extremely labor intensive and thus costly. In addition, ideally, this solution should be repeated each time the cable/bus configuration or the modules in the critical environment are modified as any change in environment configuration can alter air flow and hence temperature patterns.
Yet one other solution to the critical environment temperature disparity problem is to, in addition to cooling the ambient, provide cabinet monitoring equipment including temperature sensors inside cabinet housings that are linked to a processor. The processor can then monitor temperature in the cabinets and generate an alarm when the temperature inside any given cabinet exceeds some threshold level. In this way IT personnel are alerted when the temperature within a cabinet is dangerously high and can take steps to remedy the problem.
While the above solutions are advantageous they have some shortcomings. First, there is some loss of cooling capability prior to cooling the devices simply because cool air from the floor is released into the large critical environment.
Second, module cooling is relatively inefficient. Clearly colder cooling air facilitates more efficient cooling. In the case of ambient cooling, the air drawn over the electronic modules includes the cooling air from within the raised floor mixed with the warm exhaust air form the cabinets within the critical environment. Thus, while the air supplied to the critical environment is cold, the cooling air is relatively warm and hence the cooling function is inefficient.
Third, ambient cooling systems cannot be adjusted to increase or decrease the amount of cooling air provided to each cabinet as a function of immediate requirement. For example, at a first time all modules within a cabinet may be operating near full capacity while at a second time the modules may be operating at a small fraction of total capacity. When at full capacity, generated heat will be much greater than when at the fraction of total capacity and hence the optimal amount of cooling air to be delivered will change over time. Ambient cooling systems cannot accommodate such optimal requirements.
One attempt to address the problems with ambient cooling systems is described in U.S. Pat. No. 5,216,579 (the ""579 patent) entitled xe2x80x9cRack Based Packaging System for Computers with Cable, Cooling and Power Management Modulexe2x80x9d that issued on Jun. 1, 1993. The ""579 patent teaches a system including a power plenum, a cooling plenum and a cable plenum. The plenums are arranged adjacent each other to form a plenum construct and the construct is attached to a side or lateral wall of an electronic module cabinet such that each plenum extends along the entire vertical length of the cabinet. The plenums are positioned in logical locations with respect to each other and with respect to the configuration of the modules within the cabinet. For example, in one embodiment the power plenum is provided adjacent the back side of the cabinet and includes power outlets, the cable plenum is positioned adjacent a front side of the cabinet and provides space for data buses and the like while the cooling plenum is positioned between the other two plenums. This configuration makes sense as the electronic modules typically link to power from a rear module face while the data buses are often linked to connectors positioned on the front surfaces of the modules.
In another configuration the ""579 patent teaches that the cooling plenum may be positioned on the side of the cabinet adjacent the front cabinet wall. The ""579 patent teaches that this configuration is advantageous as the cooling air is delivered closer to the front of the servers as opposed to a side.
The cooling plenum channels cooling air directly from a raised floor up along the side of the cabinet. The cabinet includes a plurality of openings that are aligned with openings in the cooling plenum. Air pumped into the cooling plenum therefore is delivered to different parts of the cabinet to cool modules therein. Exhaust air is then directed into the ambient by fans in the back walls of server housings.
The ""579 solution delivers cooling air directly to the electronic module cabinets and therefore is much more efficient than the ambient cooling concepts described above. Nevertheless, the ""579 patent also has several shortcomings. First, to provide the best cooling pattern an air plenum should provide air along each of the front faces of the modules in the cabinet with the fans drawing the air through the servers and out to the exhaust ports. The ""579 solution provides cooing air to only one side of the cabinet. This is true even in the case where the cooling plenum is adjacent the front cabinet wall. Thus, despite recognizing that it is important to deliver cooling air to the front of each module, the ""579 patent fails to teach an optimal design that performed this function evenly across the front faces of the modules.
Second, the ""579 plenum cannot be adjusted to modify air distribution along the length of the plenum. This is in part due to the fact that the ""579 plenum has to be designed to provide air at the openings in the cabinet which typically are not adjustable. The ability to adjust air distribution along the length of the plenum is particularly important for efficient cooling as the equipment within a cabinet may be changed often and the relative positions within the cabinets of heat generating components and air flows may be modified periodically. In this regard, in a first cabinet primary heat generating components may be positioned in the cabinet bottom while in a second cabinet the primary heat generating components may be positioned in the top of the cabinet. Here, even distribution of cooling air along the entire cabinet length would not be efficient.
In addition, even where component configurations are not changed, throughout the course of a day certain electronic modules will often generate appreciably different amounts of heat such that the cooling air requirements will fluctuate throughout the day.
Third, the ""579 plenum air delivery system is completely static. That is, the delivery system cannot automatically determine when the temperature within a cabinet is at a dangerous level and cannot automatically alter the air delivery function to address the dangerous levels. For instance, assume that cables within the space below a raised floor impede the air path to several plenum inlets in one part of a critical environment. In this case the ""579 solution would not recognize that a problem exists and thus the electronic modules inside the cabinet would not receive sufficient cooling air. In systems including cabinet temperature sensors the sensors would indicate the temperature problem and IT personnel could then address the matter. However, this solution is relatively inefficient and, in some cases, can lead to system shut down if IT personnel do not respond in a timely fashion.
U.S. Pat. No. 6,188,189 (the ""189 patent) that issued on Feb. 13, 2001 and that is entitled xe2x80x9cFan Speed Control Systemxe2x80x9d teaches one system that automatically alters cooling air volume as a function of cabinet temperature. To this end, the ""189 patent teaches that dedicated temperature sensors can be positioned at various locations within a cabinet. The sensors are monitored and fan speeds are altered as a function of cabinet temperature. Other systems regulate cooling in other fashions (e.g., via damper control or cooling air temperature). While the ""189 solution advantageously provides automated control of cooling air volume, this solution to the temperature control problems is relatively expensive requiring a plurality of dedicated temperature sensors.
One other problem with a fan speed controlling system like that taught in the ""189 patent is that the space from which the fan attempts to draw air could be blocked so that the fan, in fact, draws little air and the cooling effect is minimal. For example, as in the ""579 patent, where the air is drawn from below a raised floor, as indicated above, cables buses below the floor could obstruct air flow such that even the air flow caused by a high speed fan would be minimal.
In the case of co-location companies and web-hosting companies, yet another problem with the above described systems is that the companies have no accurate way of determining how to attribute cooling costs to separate customers. The cooling costs are simply chalked up as overhead and split in some relatively arbitrary fashion among customers. For instance, one way to attribute costs to customers is by square footage of a facility required to house a customer""s servers or servers rented by the customer. This solution may require a customer to pay far more than the customer""s share of cooling costs. For example, assume a first customer""s cabinets require 50% of the total square footage of a critical environment but that the customers modules are essentially fully utilized so that the customer""s modules require 80% of the cooling that occurs during a particular month. While it would be equitable to charge the first customer for 80% of the total cooling costs, an arbitrary square foot billing system would undercharge the first customer by 30% of the total cooling costs.
Thus, there is a need for a more efficient cool air delivery system for use in critical environments. In addition, there is a need for an air delivery system that can automatically alter air volume to module cabinets based on cabinet and/or component temperature. Moreover, there is a need for a system that automatically tracks critical environment temperatures throughout a data center environment and provides information regarding the same. Furthermore, there is a need for a system whereby cooling costs can be equitably allocated to various customers.
It has been recognized that a plenum or other form of air delivery member can be constructed on the inside of an electronic module cabinet door that can deliver cool air extremely efficiently to modules inside the cabinet to increase cooling efficiency. In some embodiments the plenum includes the cabinet door while in others the plenum is a retrofit assembly that can be added to an existing door to provide the cooling air. In several embodiments cool air is pumped directly into the plenum via a conduit member that extends from a cooling air source below the cabinet.
In general terms, the present invention includes an apparatus for use with a frame defining a front, a back and first and second sides extending from the frame front to the frame back for supporting and mounting at least one electronic module, the module including a front wall and a back wall, the front wall forming at least one inlet and the back wall forming at least one outlet, the apparatus for delivering air to the at least one module and comprising at least one plenum mounted to the first side and defining a passageway adjacent the front side of the frame, the plenum including at least one opening facing the first side and a cooling air source linked to the plenum to provide cooling air to the plenum.
In some applications the plenum includes a door member and at least one wall member spaced from the door member so as to form the passageway, the door member having an edge and being hingedly linked to the frame along the edge for rotation about the edge between a closed position where the plenum is adjacent the first side and an open position where the plenum is extended from the first side. Also, the plenum may further include first and second plenum lateral walls and an end wall, the lateral walls opposing each other and traversing the distance between the door member and the wall member and the end wall traversing the distance between the lateral wall members opposite the air source.
In several embodiments the apparatus further includes a first mating member linked to the air source and a second mating member linked to the plenum and positioned proximate the first mating member when the door member is closed, the first and second mating members configured such that one of the mating members receives the other mating member when the door member is closed and the mating members together form a passage from the air source to the plenum. The air source may be positioned below the door member and the second mating member may extend upward below the door member when the door member is in the closed position. In a preferred embodiment the second mating member extends upward below the hinge.
In some embodiments the apparatus includes a conduit member positioned proximate the hinged edge of the door connecting the air source to the plenum.
In some embodiments the plenum is formed at least in part of a transparent material. The transparent material may be Plexiglass. The plenum may further include a baffle member mounted adjacent the opening for movement with respect thereto, the baffle member movable with respect to the opening such that the baffle member blocks different portions of the opening. The plenum may form a plurality of openings and the baffle member may be moveable with respect to the plurality of openings to block varying portions of the openings.
The invention also includes a cooling assembly for cooling at least one electronic module, the module including a front wall and a back wall, the front wall forming at least one inlet and the back wall forming at least one outlet, the front wall also forming a front surface. In this case the assembly includes a frame defining a front side, a back side and first and second sides that separate frame front and back sides, a rack mounted inside the frame including an upright member and at least one essentially horizontal shelf member, the module positionable on the shelf member such that the front surface faces the front side, at least one air delivery member forming at least one opening, the delivery member mounted to the frame such that the opening faces the front surface and a cooling air source linked to the delivery member to deliver cooling air to the delivery member.
Here the assembly may further include first and second lateral wall members that essentially close the first and second sides of the frame, respectively. The assembly may also include a back wall member that essentially closes the back side of the frame. In some embodiments the frame further defines top and bottom sides and further includes top and bottom wall members that essentially close the top and sides, respectively. The top wall may form at least one outlet proximate the back wall member. When in a closed position, the delivery member may block the front side of the frame.
In some applications the delivery member is hingedly mounted to the frame for movement between the closed position and an open position where the first side is unobstructed. The size of the opening formed by the delivery member may be adjustable.
The invention further includes a cooling assembly comprising an electronic module including a front wall and a back wall, the front wall forming at least one inlet and the back wall forming at least one outlet, the front wall also forming a front surface, the module including at least one operating parameter sensor, linked to a data bus and capable of communicating status of the at least operating parameter via a standard network protocol, at least one air delivery member forming at least one opening, the delivery member mounted adjacent the module such that the opening faces the front surface, a damper linked to the air delivery member and linked to the data bus, a cooling air source linked to the damper and a processor linked to the bus for receiving the status communication and for controlling the damper as a function of the status communication. One standard protocol is SNMP although other standard protocols aae contemplated.
The invention, moreover, includes an apparatus for cooling at least one electronic module inside a module cabinet, the cabinet including a door, the apparatus comprising a cooling air source linked to the cabinet, a sensor for sensing the status of the door and a controller for controlling the amount of air provided to the cabinet via the cooling air source, the controller linked to the sensor and programmed to modify the cooling air volume delivered to the cabinet as a function of the door status. Here, the controller may reduce the air delivered to the cabinet when the door is opened. In fact, in some applications the controller blocks air delivery to the cabinet when the door is opened.
These and other objects, advantages and aspects of the invention will become apparent from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention and reference is made therefore, to the claims herein for interpreting the scope of the invention.